step-1. With B as center and any convenient radius draw an arc intersecting AB at L.

Step - 2 With L as center and radius LB draw an arc intersecting the arc drawn in step 1 at M.

Step-3 With M as center and radius LB draw an arc intersecting the arc drawn in step 1 at N. { on the same side as M]

Step 4. With M and N as centers and any convenient radius draw arcs intersecting each other at C.

Step 4. Joint BC it will be perpendicular to AB